中文摘要：

通过对PFC混凝去除水中HA过程中所形成的PFC-HA絮体的研究结果表明,原水pH分别为9.0、7.0和5.0时,最佳投药量下形成的絮体的平均沉降速度之间的比值为1.17∶1.00∶0.49,而且所有絮体的水平投影方向的平均直径与垂直投影方向的平均直径的比值均接近0.85.结合Logan公式和有效密度-长轴的双对数关系计算出的絮体三维空间的分形维数Df较为可靠,在本试验中3种pH的原水下形成的PFC-HA絮体的Df均小于2.0.絮体沉降速度的变化是质量分形维数Df、有效密度和粒径等因素的变化综合影响结果,因此,絮体的Df、有效密度各自的变化趋势有可能与沉降速度的不一致.原水pH=7.0时絮体的Df稍大于原水pH=9.0时絮体的Df,但比原水pH=5.0时絮体的Df大11.73%.可见,与原水pH=9.0时形成的絮体相比,原水pH=7.0时形成了稍微密实的小絮体,但原水pH=5.0时却形成了较为疏松的、很小的絮体.在本试验的图像分辨率下,PFC-HA絮体在一维拓扑空间下的分形维数D1比较低,一般都低于1.10.基于投影面积-长轴关系计算的二维拓扑空间的分形维数D2变化趋势为样品3稍大于样品2,样品1最小；然而基于投影面积-周长计算的二维拓扑空间的分形维数D2却呈现不同的变化趋势.另外,尽管PFC-HA絮体的Df小于2,但其与基于投影面积-长轴关系计算的二维拓扑空间的分形维数D2不相等,不符合Meakin的结论,这与本试验中CCD相机的分辨率和絮体样本数量有关.

英文摘要：

The fraetal dimensions of PFC-HA floes in different topological spaces were calculated from their effective density-maximum diameter and image analysis. The ratio between the average diameters for PFC-HA floes from the horizontal projected view and the vertical projected view were close to 0.85. And the ratio among the average sedimentation rates for floes produced from HA water at initial pHs of 9.0, 7.0 and 5.0 was 1. 17：1：0.49. The mass fractal dimensions Df of PFC-HA floes at initial pH of 7.0, all less than 2.0, calculated from the bi-logarithmie relationship of effective density to maximum diameter and the Logan equation, was little greater than that at initial pH of 9.0, but 11.73% greater than that at an initial pH of 5.0. Therefore, compared with the PFC-HA floes in HA water with an initial pH of 9.0, smaller and slightly more compact floes were formed in HA water at an initial pH of 7.0, and much smaller and looser ones were formed in HA water at an initial pH of 5.0. The mass fractal dimensions Df, effective density and diameters of PFC-HA flocs affected their sedimentation rates, and neither the highest value of Df nor the effective density of PFC-HA flocs could fully determine the highest sedimentation rate. At the image resolutions in the experiments, the fractal dimensions D1 in 1D topological space were less than 1. 10. The D2 （lgA-lgdL） of PFC-HA flocs formed in HA water at initial pH of 5.0 was a little greater than that at initial pH of 7.0, and the smallest one was found in HA water at initial pH of 9.0. But D2 （lgA-lgP） of PFC-HA flocs in HA water at different initial pH values showed a different trend. In addition, not unlike the conclusion from Meakin, the mass fractal dimensions Dr of PFC-HA flocs were not equal to their DE （lgA-lgdL） values, which may be caused by image resolution and number of flocs sampled.